#!/usr/bin/env python3
#------------------------------------------------------------------------------#
#  DFTB+: general package for performing fast atomistic simulations            #
#  Copyright (C) 2006 - 2020  DFTB+ developers group                           #
#                                                                              #
#  See the LICENSE file for terms of usage and distribution.                   #
#------------------------------------------------------------------------------#

from numpy import oldnumeric as num
from numpy import linalg as linal
import math
import sys
import re
import optparse as opt

SCRIPT_NAME = "cubemanip"

# Tolerance for positions to be treated as equal
tolerance = 1.0e-5

# Pattern for the argument parsing
patVar = re.compile(r"\((\$(?P<number>\d+))\)")

# Help text
helpTxt = """
%(name)s <expr> [ <cubeFile1> [ <cubeFile2> [ ... ]]]
      
Combines the passed cube files (<cubeFile1>, <cubeFile2>, ...)  according the
expression <expr> to a new cube file.  The cube files provided as arguments
after the expression must be referenced in the expression as ($n), where n the
index of appropriate file is. The expression can be any arbitary expression
which is valid in python using the Numerical and LinearAlgebra packages and
results in a float or a float array. Unless the '-d' option is passed, the
result must have the same shape, as the data arrays in the cube files. The
references in the expression are substituted by the data arrays of the
appropriate cube files. The resulting cube file (dumped on stdout!) will have
the same header as the first file, while its data array is created by evaluating
the expression <expr>. The number of cube files passed as arguments must be
higher than the maximal reference index in the expression.

Please note, that <expr> may not contain any whitespace characters.

You have access to the following variables:
  origin   -- origin of the grid in the first file as (3,) shaped array
  gridVecs -- grid vectors in the first file as (3,3) shaped array
  nGrid    -- nr. of grid units along the grid vectors as (3,) shaped array

example:

%(name)s '0.25*($1)+0.25*($2)+0.5*($3)' file1.cube file2.cube file3.cube
Weighted sum of three cube files.

%(name)s -d 'sum(sum(sum(($1)**2)))' file1.cube
Sums up the square of the function stored in the cube file.

%(name)s -d 'sum(sum(sum(($1))))*determinant(gridVecs)' file1.cube
Integrates the function in the cube file.
""" % { "name": SCRIPT_NAME }


def error(msg):
  """Prints an error message and stops"""

  print >>sys.stderr, "Error: %s" % msg
  sys.exit(1)



def warning(msg):
  """Prints a warning message"""

  print >>sys.stderr, "Warning: %s" % msg



class cube:
  "Empty type to carry information about cube headers"
  pass



def getCubeRepr(fname):
  """Reads in a cube file with a given name"""

  try:
    fp = open(fname, "r")
    lines = fp.read().split("\n")
    fp.close()
  except IOError as ex:
    error("Could not open file '%s'\n%s" % (fname, ex))
  cc = cube()
  words = lines[2].split()
  cc.nAtom = int(words[0])
  cc.origin = num.array([ float(s) for s in words[1:4] ])
  words = (" ".join(lines[3:6])).split()
  cc.nGrid = tuple([ int(s) for s in [words[0], words[4], words[8]]])
  tmp = [ words[i] for i in (1, 2, 3, 5, 6, 7, 9, 10, 11) ]
  cc.gridVecs = num.reshape(num.array([ float(s) for s in tmp ]), (3,3))
  words = (" ".join(lines[6:6+cc.nAtom])).split()
  tmp = [ words[i] for i in range(0, 5*cc.nAtom, 5) ]
  cc.species = num.array([ int(s) for s in tmp ])
  tmp = []
  for ii in range(2, 5*cc.nAtom, 5):
    tmp.append(words[ii])
    tmp.append(words[ii+1])
    tmp.append(words[ii+2])
  cc.coords = num.reshape(num.array([ float(s) for s in tmp ]), (-1, 3))
  data = []
  for line in lines[6+cc.nAtom:]:
    data.extend([ float(s) for s in line.split()])
  cc.data = num.array(data, num.Float)
  nAllData = cc.nGrid[0] * cc.nGrid[1] * cc.nGrid[2]
  if cc.data.shape[0] != nAllData:
    error(("Data in '%s' inconsistent with header (expected: %d, got: %d)"
           % (fname, nAllData, cc.data.shape[0])))
  cc.data = num.reshape(cc.data, cc.nGrid)
  
  return cc



def dumpCubeFile(cc):
  """Dumps a cube file to stdout"""

  print >>sys.stdout, "Cube file created by cubemanip"
  print >>sys.stdout, "Cube file created by cubemanip"
  print >>sys.stdout, ("%10d %18.10E %18.10E %18.10E"
                      % (cc.nAtom, cc.origin[0], cc.origin[1], cc.origin[2]))
  for ii in range(3):
    print >>sys.stdout, ("%10d %18.10E %18.10E %18.10E"
                        % (cc.nGrid[ii], cc.gridVecs[ii][0], cc.gridVecs[ii][1],
                           cc.gridVecs[ii][2]))
  for ii in range(cc.nAtom):
    print >>sys.stdout, ("%4d %18.10E %18.10E %18.10E %18.10E"
                         % (cc.species[ii], 0.0, cc.coords[ii][0],
                            cc.coords[ii][1], cc.coords[ii][2]))
  for i1 in range(cc.nGrid[0]):
    for i2 in range(cc.nGrid[1]):
      line = []
      for i3 in range(cc.nGrid[2]):
        line.append("%18.10E" % cc.data[i1][i2][i3])
        if len(line) == 4:
          print(" ".join(line))
          line = []
      if len(line):
        print(" ".join(line))



def dumpData(data):
  """Dumps an arbitary shaped numerical array"""

  shape = data.shape
  if not len(shape):
    print("%18.10E" % data)
    return
  
  curShape = [0,] * len(data.shape)
  finished = False
  carry = False
  while not (curShape[0] == 0 and carry):
    line = []
    curShape[-1] = -1
    for ii in range(shape[-1]):
      curShape[-1] += 1
      line.append("%18.10E" % data[curShape])
      if len(line) == 4:
        print(" ".join(line))
        line = []
    if len(line):
      print(" ".join(line))
    carry = True
    for ii in range(len(shape)-1, -1, -1):
      if carry:
        curShape[ii] = curShape[ii] + 1
        if curShape[ii] == shape[ii]:
          curShape[ii] = 0
          carry = True
        else:
          carry = False
      else:
        break
    


def main():
  """Main program"""

  # Parse command line options
  parser = opt.OptionParser(usage=helpTxt)
  parser.add_option("-d", "--data-only", action="store_true", dest="data_only",
                    default=False,
                    help="Dump only data without cube header. The resulting "
                    "data may have different shape as as the input data.")
  (options, args) = parser.parse_args()

  if len(args) < 1:
    error("No expression specified!\nType '%s -h' for help." % SCRIPT_NAME)
    sys.exit(1)
  expr = args[0]

  # Look for the highest reference index
  maxArg = 0
  start = 0
  match = patVar.search(expr)
  while match:
    argNum = int(match.group("number"))
    if argNum > maxArg:
      maxArg = argNum
    match = patVar.search(expr, match.end())

  if maxArg == 0:
    error("Expression contains no parameters!")
    
  if len(args) < maxArg + 1:
    error("Missing files! You must specify at least %d cube file(s)." % maxArg)

  # Read in the necessary cube files
  fnames = args[1:]
  cubeList = [ getCubeRepr(fname) for fname in fnames ]

  # Check for compatibility
  c0 = cubeList[0]
  for ii in range(1, len(cubeList)):
    if cubeList[ii].nGrid != c0.nGrid:
      error(("Grid points in '%s' and '%s' are incompatible!"
             % (fnames[0], fnames[ii])))

    if cubeList[ii].nAtom != c0.nAtom:
      warning("Nr. of atoms in '%s' and '%s' differ" % (fnames[0], fnames[ii]))
    elif num.any(cubeList[ii].species != c0.species):
      warning(("Specie indexes in '%s' and '%s' differ"
               % (fnames[0], fnames[ii])))
    elif (max(num.sqrt(num.sum((cubeList[ii].coords - c0.coords)**2, -1)))
        > tolerance):
      warning("Coordinates in '%s' and '%s' differ!" % (fnames[0], fnames[ii]))

    if (num.sqrt(num.sum((cubeList[ii].origin - c0.origin)**2)) > tolerance):
      warning("Origins in '%s' and '%s' differ!" % (fnames[0], fnames[ii]))
    if (max(num.sqrt(num.sum((cubeList[ii].gridVecs - c0.gridVecs)**2, -1)))
        > tolerance):
      warning("Grid vectors in '%s' and '%s' differ!" % (fnames[0], fnames[ii]))
    if (max(num.sqrt(num.sum((cubeList[ii].gridVecs - c0.gridVecs)**2, -1)))
        > tolerance):
      warning("Grid vectors in '%s' and '%s' differ!" % (fnames[0], fnames[ii]))


  # Evaluate expression
  data = [ cc.data for cc in cubeList ]
  pyExpr = patVar.sub(r"(data[\g<number>-1])", expr)
  varDict = { "data": data, "origin": c0.origin, "gridVecs": c0.gridVecs,
              "nGrid": c0.nGrid }
  varDict.update(num.__dict__)
  varDict.update(linal.__dict__)
  try:
    result = eval(pyExpr, varDict)
    resArr = num.array(result, num.Float)
  except (Exception,) as exp:
    error("Unable to evaluate you expression!\n%s"
          % exp)

  # Check shape of the result
  if (not options.data_only) and resArr.shape != c0.data.shape:
    error(("Resulting shape %s is incompatible with the original one %s"
           % (str(resArr.shape), str(c0.data.shape))))

  # Write out the result
  if options.data_only:
    dumpData(resArr)
  else:
    c0.data = resArr
    dumpCubeFile(c0)


if __name__ == "__main__":
  main()



### Local Variables:
### mode:python
### End:
